Apparatus for applying liquid to slides



March 11, 1969 J. B. MCCORMICK ETAL 3,431,886

APPARATUS FOR APPLYING LIQUID TO SLIDES Filed June '7, 1965 Sheet of 5FIGURE I.

Q I v, 4 /Z l INVENTORS JAMES 8. MC CORMICK LEIGHTON C. JOHNSON 3ATTORNEY March 11, 1969 .1. B. M cbRlvucK ETAL 3,431,336

APPARATUS FOR APPLYING LIQUID TO SLIDES m mEDDC Sheet Filed June 7, 19658, ATTORNEY March 11, 1969 J. a. MCCORMICK ETAL 3,431,885

APPARATUS FOR APPLYING LIQUID TO SLIDES Sheet Filed June 7, 1965INVENTORS JAMES B. MC CORMlCK LEIGHTON C. JOHNSON BY E ATTORNEY March 111969 J. B. M CORMICK ETAL 3,431,386

APPARATUS FOR APPLYING LIQUID To SLIDES Filed June 7, 1965 Sheet 4 of sl l l 1 J 3/ FIGURE 5. l 92 (PD/I33" JAMES 5. MC CORMICK LEIGHTON C.JOHNSON ATTORNEY March 11, 1969 J, M CORMICK ETAL 3,431,886

APPARATUS FOR APPLYING LIQUID TO SLIDES Filed June 7. 1965 Sheet 5 or 5FIGURE 6.

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r I rr INVENTORS ATTORNEY United States Patent 3,431,886 APPARATUS FORAPPLYING LIQUID T0 SLIDES James Benjamin McCormick, La Grange, andLeighton Clifford Johnson, Westmont, lil., assignors, by mesneassignments, to Miles Laboratories, Inc, Ellrhart, lind., a corporationof Indiana Continuation-impart of application Ser. No. 379,822, July 2,1964. This application June 7, 1965, Ser. No. 461,613 US. Cl. 11810Claims Int. Cl. B05c 5/02, 3/20 ABSTRACT OF THE DISCLOSURE Apparatus andthe method of operation thereof is described for conveying objects, suchas microscope slides, over a flat liquid applying surface and injectiinga treating liquid into the space between the object and the surface.Helical conveying apparatus is also described for moving the slides froma substantially vertical position to a substantially horizontal positionprior to conveying the slides over the liquid applying surface.

This application is a continuationin-part of our copending applicationSer. No. 379,822 filed on July 2, 1964, now abandoned.

The present invention relates to apparatus for advancing an objectthrough a station at which one face of the object is treated. Moreparticularly, the invention relates to apparatus for applying a liquidto one face of a microscopic slide. Still more particularly, theinvention relates to apparatus for automatically and successivelystaining material carried on a plurality of microscopic slides.

In the microscopic examination of certain material, particularlycellular materials such as blood, tissue, etc., it is customary to placea smear of a liquid or substrate containing the material (e.g., a smearof plasma containing blood cells), or a thin section of the materialitself (e.g., a thin slice of animal tissue) on a transparent plate orslide. Thereafter, the material is stained by subjecting it to contactwith solutions which stain or dye only certain constituents of the cellto thus provide a contrast which facilitates visual examination.

Various staining procedures are utilized to produce different desiredeffects. For example, a solution may be employed to color a transparentsubstrate and thus provide contrast to essentially colorless cells;other solutions may be utilized to effect color differences betweenvarious parts of a cell. Solutions may be used to stain only portions ofa cell, e.g., the nuclei and not the cytoplasm and, in a procedure knownas negative staining, the cells may be caused to appear colorlessagainst a colored background. Certain of the procedures are relativelysimple and require the use of only a few solutions. Others, however, arecomplex and require successive applications of a relatively large numberof different solutions.

In many of these staining procedures, certain of the solutions merelyprepare or fix the substrate whereas the actual stains are made by oneor more natural or synthetic dyes. The dyes selected are, of course,suited for the type of cell and the staining desired. The oxazine dyes,the triphenylmethane dyes, and the thiazine dyes are examples of somefamilies of dyes that are commonly used.

In a conventional staining procedure it has been the general practice todip the slide successively into each of a series of containers holdingan appropriate solution, the slide being allowed to remain in eachsolution for a predetermined time interval of perhaps several minutesbefore being removed and dipped into a succeeding soluice tion. Usually,the last container holds a wash, such as water, after which the slide isdried for examination. Regardless of what solutions are used, however,each step in the staining operation is usually performed manually by atechnician.

Depending upon the nature of the material being stained and the type ofstaining desired, as many as twelve solutions may be required and theoverall proce dure, when performed in the above-described manner, isthus quite time-consuming. The fact that many slides are frequentlyinvolved merely multiples the problem. Furthermore, when successiveslides are passed through the same container of solution, as is the casewhere dipping is employed, there is a danger of contamination of thesolution. This danger increases when the same solution is used indifferent staining procedures for different types of materials andsubstrates.

It is an object of the present invention to provide an improvedapparatus for treating one face of a generally flat object. It isanother object of the present invention to provide an improved apparatusfor automatically and successively applying liquid stain to materialscarried on a plurality of slides. Still another object of the inventionis to provide an improved apparatus for automatically staining materialcarried on a slide by successively effecting contact between suchmaterial and each of a plurality of solutions. A further object of theinvention is to provide an improved apparatus for automatically stainingmaterial carried on one face of a slide by successively applyingsolutions only to that face of the slide carrying the material. It is astill further object of the invention to provide an improved apparatusfor automatically staining rnaterial carried on a plurality of slides byapplying a metered quantity of previously unused solution for eachapplication to each slide, and it is still a further object of thisinvention to provide an improved control system for controlling theoperation of a slide staining apparatus. These and other objects of theinvention are more particularly set forth in the following detaileddescription and in the accompanying drawings wherein:

FIGURE 1 is a perspective view of the apparatus showing various of thefeatures of the present invention;

FIGURE 2 is an enlarged front view of the apparatus shown in FIGURE 1with the lid, the control panel and the front portion of the housingremoved, and with some parts broken away for clarity of illustration;

FIGURE 3 is an enlarged top view of the apparatus shown in FIGURE 1,with the lid, the control panel and the front portion of the housingremoved and with some parts broken away for clarity of illustration,some slides being shown in phantom;

FIGURE 4 is a sectional side view taken along line 4-4 of FIGURE 2;

FIGURE 5 is a schematic diagram of the electrical control circuitry ofthe apparatus shown in FIGURE 1; and

FIGURE 6 is a sectional side view taken on a plane similar to that ofFIGURE 4 of an alternate embodiment of the invention.

Very generally, the present invention provides apparatus forautomatically applying liquid to one face of a slide the applicationbeing of a single or of multiple solutions as selected. This apparatusis particularly useful for automatically staining material carried onone face of each of a plurality of slides. In the embodiment illustratedin FIGURES 1 to 4, a slide-staining apparatus 11 is provided whichcomprises a plurality of treating, i.e., liquid-applying, stations 13,13' and 13" and a feed mechanism 15 for advancing generally flatobjects, such as transparent glass slides 17, past said plurality oftreating stations. A liquid-applying device located at each of m? thestations automatically subjects one face of each slide 17 to contactwith a metered quantity of desired liquid.

To provide a compact apparatus capable of handling a fairly large numberof slides, the feed mechanism is designed to accept slides 17 aligned ingenerally parallel face-to-face relationship and each disposed so as torest upon a longitudinal edge and thereby lie in generally verticalplanes. As the slides 17 are advanced by the feed mechanism 15, they arerotated so as to be aligned in generally parallel edge-to-edgerelationship and thereby lie in a generally horizontal plane as theypass through liquid-applying stations. After the slides 17 have passedthe last of these stations, they are returned to their previousgenerally vertical orientation. A drying and collection station 19 islocated adjacent the output end of the feed mechanism 15, which firstdries the slides 17 and then automatically removes them from the feedmechanism 15.

Now referring more particularly to the drawings, the apparatus 11includes a base 21, a pair of end plates 23 and 25, a back plate 27, acontrol panel 45, and a top cover or lid 29 which is hinged to the backplate 27 and when closed is supported by inwardly directed flanges 31and 33 on the end plates 23 and respectively. A side intermediatesupport plate 37 (FIGURE 2) and rear intermediate support plates 39, 41and 43 (FIGURE 4) extend upwardly from the base 21 and, together withthe base, the end plates 23 and 25, and the control panel 45, supportthe various operative components of the apparatus 11.

The feed mechanism 15 includes a track which extends longitudinally ofthe apparatus 11 and is defined by a pair of generally parallel rails 47and 49 which are spaced apart horizontally a distance less than thelength of a standard glass slide which, conventionally, is about threeinches in length and one inch in width. Rails 47 and 49 may be formedfrom separate bars or rods, for example. Preferably rails 47 and 49 areformed from rip-turned edges of a track member 51 which will bedescribed in more detail later. In the operation of the apparatus, theslides 17 straddle or span the rails 47 and 49 with each rail engagingeach slide at a point spaced inwardly from an end thereof (FIGURE 3). Ifdesired, the slides may be inclined slightly during their movement alongthe track so that any applied liquid may have a greater tendency todrain therefrom. One way to accomplish this is to have the upper surfaceof the rear rail 47 elevated slightly relative to the front rail 49.This difference in elevation of rails 47 and 49 is shown in anexaggerated manner in FIGURES 2, 4 and 6.

To advance the slides 17 along the rails 47 and 49 and to maintain apredetermined spacial relationship between said slides, the feedmechanism 15 includes a pair of conveyor elements 53 and 55 which flankthe rails 47 and 49. The conveyor element 53 i positioned behind andextends generally parallel with the rear rail $7 and may be in the formof a heavy wire wound to provide, for example, a left-hand helix (usingstandard screw terminology). The conveyor element 53 is supported by astationary rod 57 extending coaxially therethrough and suitablysupported at its opposite ends by the end plates 23 and 25. The conveyorelement 55 is positioned in front of and extends generally parallel withthe front rail 49 and may be in the form of a heavy wire wound toprovide, for example, a right-hand helix. The conveyor element 55 issupported by a stationary rod 59 extending coaxially therethrough. Theconveyor elements 53 and 55 are preferably substantially identicalexcept for the direction of their helical configurations. The pitches ofthe helices which form conveyor elements 53 and 55 vary along the lengthof conveyor elements 53 and 55. At the right hand end of the conveyorelements, as seen in FIGURES 1 and 3, the pitches of the conveyorelements are such that the turns of the helices are quite closetogether. The gap between adjacent turns of a given helix being onlyslightly greater than the thickness of the flat object to be treated,e.g., a glass slide. The pitches of the helices change in theirintermediate portions so that the gap between adjacent turns is enlargedto a distance slightly greater than the Width of the flat object to betreated. At the left hand end of the conveyor elements, the pitches ofthe helices again are such that the turns of the helices are quite closetogether. The changes in pitch of each of the helices 53 and 55 enablethe slides to be rotated from a generally vertical position (normal tothe plane of the track) to a generally horizontal position (parallel tothe plane of the track) and then back to a generally vertical positionas the slides move along rails 47 and 4-9. This rotation of the slideswill be described in more detail later. Because the helices of theconveyor elements 53 and 55 are designed principally for use with glassslides, they are preferably made from a material which withstands wearagainst glass, such as chrome plated stainless steel wire. When theslides are to be inclined slightly, as described above, rod 59 may be ata slightly lower elevation than rod 57 to accommodate the inclineddisposition of the slide 17 positioned on the inclined track member 51wherein rail 47 is elevated slightly relative to rail 49.

The inner diameters of the helical conveyors 53 and 55 are somewhatgreater than the diameters of the rods 57 and 59 which they surround sothat the helical conveyors can be freely rotated thereabout said rods ina manner soon to be described. In addition, the spacing between theconveyors 53 and 55 is such that the minimum distance between conveyors53 and 55 is less than the length of a standard slide. Thus, slides 17,engaged by or supported upon the rails 47 and 49, are positioned withtheir ends inserted between adjacent turns of the helicals 53 and 55 andare maintained in spaced relation to one another thereby. An insidesegment (facing rod 57) of rod 59 is removed providing a fiat chordalsurface 61 which cts as a guide for the adjacent edge of slide 17.Inside end segments of rod 57 are similarly provided with flat chordalsurfaces 63. The central portion of rod 57 is cut away to provide a flatsurface connecting and substantially coplanar with flat surfaces 63 anda downwardly facing shoulder 65 which is positioned to overlap the rearends of slides 17 as they are moved along the rails 47 and 49, as willbecome more apparent shortly. The spacing between rods 57 and 59 is suchthat the distance between flat chordal surfaces 61 and 63 is onlyslightly greater than the length of a standard slide. To improve clarityof illustration, the glass slides 17, which are shown in FIG- URES 1 and6, are omitted from FIGURE 2 and are shown in phantom in FIGURES 3 and4.

Rotation of the helicals 53 and 55 is accomplished by drive meansincluding similar sprocket wheels 66 rotatably carried on each end ofeach rod 57 and 59. Each sprocket wheel 66 includes an inwardly facingshoulder to which the adjacent end of a respective helical is attached,as by a screw 67. The drive means further includes an electric motor 69(FIGURES 2 and 3) having an output shaft 71 which has a small sprocket73 afiixed thereto which is connected via a short roller chain 75 to alarger sprocket '77, afiixed to a drive shaft 79. The shaft 79 extendslongitudinally completely across the apparatus 11 and is appropriatelyjournalled in bearings carried by the end plates 23 and 25. Similardrive sprockets 81 are fixedly mounted on the shaft '79 near each endthereof, and similar roller chains 83 connect the sprockets 81 and theadjacent two sprocket wheels 66 at the respective ends of the apparatus.The roller chains 83 are further engaged with idler sprockets 85 whichare rotatably mounted on the inner surfaces of end plates 23 and 25.

It will be noted that by virtue of the manner of connection of thechains 33 to the sprocket wheels 66, the helicals 53 and 55 are rotatedin opposite directions, the rear helical 53 being rotated in acounter-clockwise direction as viewed in FIGURE 4, whereas the fronthelical 55 is rotated in a clockwise direction. Accordingly, sinceinjected into the space between the upper surface 109 of platen 105 andan overlying slide to thereby contact with said liquid the lower surfaceof the slide and the material carried thereby. Since the lower face ofslide 17 is in close proximity to platen surface 109, e.g., a spacing ofa few thousandths of an inch, the surface tension of the injected liquidis sufiicient to completely fill the laminar volume between these twoflat surfaces. As the slide advances along the rails 47 and 49 andacross the platen 1615, the entire lower surface area of the slide whichpasses in faceto face relation with surface 109 of platen 105 is thusbrought into contact with the liquid and the material carried thereby issimilarly contacted by the liquid. The surface tension of the liquidcauses said liquid to be retained in the space between the platen 105and slide 17 until the slide has passed completely beyond the platen,and as the slide leaves the left hand edge of the platen 105, the liquidis wiped from the slide due to the tendency of the liqui to adhere tothe platen rather than to the slide. Thus, the slide 17 is only moist asit proceeds toward the next station 13' and has no droplets of liquidadhering to it. The liquid wiped from the slide flows into the recessedportion 107 of track 51, then into a drain 113 which communicates with adrip tray 35 removably positioned thereunder.

As shown in FIGURE 3, the left-hand edge of platen 105 is positioned atan acute angle with respect to the front edge of the platen such thatthe leading edge of the slide 17 is wiped in a downward direction as theslide passes beyond the platen 105. This aids in wiping and also inefiicient collection of the wiped liquid at the lower region of therecessed portion 107 of track member 51.

As shown in FIGURE 3 the platens 105 and 105' are preferably formed froma unitary member having a recess 112 extending from front to rearbetween said platens. A liquid injecting orifice 111' is provided in therecess 112 so that after a slide leaves the platen 105 of firstliquidapplying station 13, it then passes over orifice 111 and thesecond liquid-applying station 13'. When the lower face of slide 17 ispositioned over at least a portion of the upper surface 109 of platen105', a predetermined quantity of liquid is injected from orifice 111against the lower face of the slide. This injected liquid then flowsinto the laminar space between the lower face of the slide and the uppersurface 109" of platen 105. The recessed portion 112 acts a liquidreservoir to provide liquid for this laminar space.

As the slide 17 is slowly advanced across platen 105, there is acirculatory motion set up in the liquid film between the lower face ofthe slide and the upper surface 109' of said platen. This circulatorymotion tends to cause desired mixing of the liquid film with the liquidretained on the slide from the previous station. In the preferred formof the invention, grooves 115 are placed in the upper surface 109 ofplaten 105' to promote this circulatory motion and mixing action. Thegrooves 115 act as capillary channels which conduct the liquid acrossthe face 109 of the platen 105'. The grooves 115 are preferablypositioned at a generally obtuse angle with respect to the front edge ofthe platen such that the capillary action draws the liquid upward alongthe slide as it passes over the platen and grooves. The grooves 115 may,however, be positioned at an acute angle with respect to the front edgeof the platen such that the capillary action draws the liquid downwardalong the slide as it passes over the platen and grooves. The number,size and specific location of the grooves will vary depending upon theparticular staining or liquid-applying procedures being employed. It iswithin the knowledge of those skilled in the art to determine theseapparatus variations.

As a slide 17 leaves the left-hand edge of platen 105, the excessapplied liquid is then wiped off the slide in the same manner as atplaten 105. The slide then passes over platen 105" of the thirdliquid-applying station 13" where liquid is injected through orifice111" formed in the upper surface 109" thereof, and the lower face of theslide is exposed to the injected liquid in the same manner as atstations 13 and 13' described above. The slide is also wiped by theleft-hand edge of platen in a manner described above. To insuresubstantially complete removal of excess liquid from the lower face ofthe slide, it is passed over a platen 117 having an upper surface 119 ofreduced area disposed in substantially the same plane as the platenupper surfaces 109, 109' and 109 and aligned with the front edgesthereof. Surface 119 is located so as to wipe oif any droplets which mayhave collected on the lower surface of a slide passing thereover.

The orifices 111, 111' and 111" described above can be located in anyconvenient place on or adjacent to respective platens 105, 105 and 105".The orifice locations shown in FIGURE 3 are employed when the trackmember 51 is tilted slightly so that rail 49 is slightly lower than rail47. The upper surfaces 109, 109' and 109" of the platens 105, 105' and105" are inclined downwardly toward the front of the apparatus. Whenliquid is introduced into the space between the lower face of the slideand the upper surfaces of the platens from orifices 111 and 111' atstations 13 and 13, it is desirable to have such liquid be introduced atthe lower portion of such space and thus push any interfering air insuch space out through the top of the space. In the washing step of thethird stage 13", it is desirable to have quick and complete contact ofthe lower face of the slide with the washing liquid. Orifice 111" isthus located at the top of platen 105" to enable a film of liquid toflow down under the influence of gravity over surface 109" prior to thepassage of the slide over surface 109".

As will be noted in FIGURE 3, each platen is of a width, measured in adirection from rail 47 toward rail 49, slightly less than the length ofa slide measured in the same direction so that the film of liquid is incontact with a major portion of the lower face of the slide as the slideis moved across the platen. The length of the platen, measured in adirection from right to left along track member 51, determines thelength of time during which the liquid remains in contact with thematerial on the slide and hence, varies with the treatment to beaccomplished. In the illustrated embodiment, the tfirst platen 105encountered by the slide has a length about 1% times the width of astandard slide, the second platen 105 has a length over five times thewidth of a standard slide, while the length of the last platen 105" isless than the width of a standard slide.

Track member 51 is preferably formed as a single element containingrails 47 and 49, platens 105, 105' and 105", recessed portion 107,orifices 111, 111 and 111", recess 112, drain 113, grooves and platen117. Such single element can conveniently be formed by metal molding.

To provide timely injection of liquid at each liquidapplying station, aliquid pumping and switching mechanism is provided in association witheach of the liquidapplying stations. The switching mechanism for station13 includes a horizontally disposed shaft 121 extending from front torear and suitably journalled at its rear end near the intermediatesupport plate 39. The shaft 121 extends through a bearing in theintermediate support plate 43 and overhangs slightly the track 51,terminating at a point between the rails 47 and 49. A depending finger123 is rigidly alfixed to the front end of the shaft 121 and is ofsufficient length so that it is adapted to be engaged by the leadingedge of the slides 17 moved along the track When the finger 123 ispivoted through contact with moving slide 17, the shaft 121 is rotated,causing a cam 125 afiixed to the rear end of the shaft to rotate andactuate a normally open lever switch 127. This activates a liquidsupplying means causing liquid to flow through orifice 111. The weightof the finger 123 together with the force of the spring return on switch127 is such to helical 53 is left-handed and helical 55 is right-handedrotation thereof as described above causes slides 17 supported betweenthe turns thereof to be advanced from right to left across the apparatus(FIGURES 1, 2 and 3). Of course, if two right-handed helices or twoleft-handed helices were used, the chain drive would be modified so thatthey would both be driven in the same direction. However, theillustrated arrangement is preferred because it reduces or eliminatesfriction which might tend to undesirably tilt the slides 17 on the rails47 and 49 if two helicals wound in the same manner were used.

As best seen in FIGURES 1 and 3, slides 17 which are vertically seatedin the input end of the feed mechanism 15, at the right-hand side of theapparatus 11, are advanced to the left past the various liquid applyingstations 13, 13' and 13" incident to rotation of the helicals 53 and 55.At the input end, the turns of the helicals 53 and 55 are quite closetogether, the gap between adjacent turns being only slightly greaterthan the thickness of the flat object to be treated, e.g., a glassslide. However, the pitches of the helicals change in their intermediateportions so that the gap between adjacent turns is enlarged to adistance slightly greater than the width of the flat object to betreated. This construction enables the flat objects handled, as they areadvanced from right to left, to be rotated from the verticalface-to-face relationship to a generally horizontal edge-to-edgerelationship in which the lower faces thereof rest on the rails 47 and49, as distinguished from the prior relationship wherein only the lowerlongitudinal edges of the flat objects touched the rails. Whenmicroscopic slides are handled in the illustrated apparatus the materialto be stained is carried by the lower face of the slides when the lattertravel in the horizontal position past the liquid-applying stations.

More specifically, as the slides 17 in generally vertical face-to-facedisposition are advanced into the sections of the helicals 53 and 55wherein the change in pitch occurs to increase the gap between adjacentturns, their upper edges are slowly tilted forwardly in the direction ofadvancement, i.e., the upper edge of the slide becomes the slide leadingedge and the bottom edge of the slide becomes the slide trailing edge.In order to assure that this initial transition from the generallyvertical position to the generally horizontal position takes place asplanned, a barrier arm 103 (see FIGURE 3), preferably constructed of aresilient material such as rubber, is attached to track member 51 in alocation where it successively engages each of the slides 17 near thelower edge thereof at the position along the feed mechanism 15 where thepitch of the helicals 53 and 55 begins to change. The frictionalengagement of the lower edge of a slide 17 by barrier arm 1193 tends tohold the lower edge of the engaged slide in place While the upper edgeof said slide is free to move forward and downward as the helicals 53and 55 advance the slide along rails 47 and 49 and as the spacingbetween turns of helicals 53 and 55 increases. Other barrier means canalso be used in any convenient manner to aid in turning the slides froma generally vertical position to a generally horizontal position.

After passing the various liquid-applying stations, 13, 13 and 13", theadvancing slides 17 are returned to the generally vertical face-to-facerelation as they approach the left-hand end of the apparatus 11, andmove into the left-hand end portion of the helicals 53 and 55 which areclosely wound. At the point of this second pitch transition, it can beseen that the helicals 53 and 55 lift the leading edge of successivegenerally horizontal slides 17 upwardly and rearwardly into asubstantially vertical orientation. This rotation of the slides is aidedby lugs 58 (see FIGURE 3) attached to helicals 53 and 55 near the pointof second pitch transition. These lugs pass up under the leading edge ofthe adjacent slide and start the lifting motion. The change in pitch ofthe helicals 53 and 55 completes the slide rotating action. Thus, theslides 17 are in vertically disposed face-to-face relation when theyenter the drying and collection station 19.

As described above, the feed mechanism 15 maintains the flat objects tobe treated, such as glass slides, in closespaced generally verticalface-to-face relation both before and after they pass through thetreating stations. These vertical dispositions have several advantages.First, in such vertical positions, the slides occupy a relatively smallamount of track space and a track of much lesser length is capable ofserving a given number of slides as compared with track length requiredwhen all the slides are continuously maintained in a generallyhorizontal edgeto-edge disposition. Viewed in another way, a trackhaving a given length can accommodate a substantially larger number ofslides in vertical face-to-face relation than it can in edge-to-edgerelation. A large number of vertically disposed slides can be placed inthe input end of the apparatus, thus permitting continuous operation ofthe apparatus, without the constant attentions of a technician. Thevertical disposition of the slides at the output or drying andcollection end of the apparatus has additional advantages. As describedbelow, the slides are dried by blowing air over them. The verticalposition of the slides facilitates drainage and aids in obtainingdesirable drying air flow over the slides. Also, the slides inclosely-spaced vertical disposition take a relatively long period oftime to pass through the output end of the apparatus and are thussatisfactorily dried.

Referring to FIGURE 5 which illustrates an electrical circuit for theapparatus, the motor 69 of the drive means for rotating helicals 53 and55 is connected in series with a speed control means 87, a basket switch89, an onoff switch 91 and a fuse 93 to a conventional source ofelectrical power (not shown). An indicator light 95 which is illuminatedby closure of switch 91 is connected in parallel with the power source.The speed control means 87 includes, for example, a variable resistor 97in parallel with a fixed resistor 99 and a diode 101. A means of varyingthe speed of the motor 69 is desirable in order to increase theversatility of the apparatus 11 by permitting variation in the speed atwhich the helicals 53 and 55 are rotated and thereby a variation in thespeed at which the slides 17 are advanced along the rails 47 and 49. Formany applications, however, a constant speed motor operating atapproximately one revolution per minute is satisfactory.

FIGURE 5 also shows a basket indicator light 157, buzzer 155, liquidlevel switch 145, liquid level indicator light 147, pumps 133, 133' and133", pump switches 127, 127 and 127", triple pole pump priming switch139 and blower 149. These circuit elements will be described in moredetail later.

Referring now to the treatment of a generally flat object, asillustrated by application of liquids to a slide for staining asubstance positioned thereon, the illustrated apparatus 11 includesthree separate liquid-applying stations 13, 13 13". It is to beunderstood, of course, that any number of such stations may be providedand that the number shown is only illustrative of a particular stainingprocedure, namely, the Wright procedure for staining blood smears. Incarrying out the Wright procedure in the improved apparatus, thestaining liquid is applied at the first station, a bulfer liquid isapplied at the second station and a washing liquid is applied at thethird station.

Each of the liquid-applying stations, exemplified by station 13,includes a stationary platen 1G5 (FIGURE 3) securely mounted within arecessed portion 107 of track member 51 and between the rails 47 and 49.The platen is positioned so that its upwardly facing surface 109 isparallel with and closely subjacent to the plane of the upper surfacesof the rails 47 and 49 so as to be parallel with and in close proximityto the lower face of a slide 17 supported by rails 47 and 49 andpositioned over said platen. The platen 1115 is provided with an orifice111 through which a predetermined quantity of liquid can be cause theswitch 127 to open and the shaft 121 to rotate to its initial positionafter the finger 123 is no longer engaged by the slide 17. Similarswitching mechanisms are triggered by fingers 123' and 123" for stations13' and 13" respectively.

As shown in FIGURE 5, the motors for pumps 133, 133' and 133 areconnected to a power source (not shown) through pump switches 127, 127'and 127", respectively, as well as basket switch 89, on-oif switch 91and fuse 93. The pump motor for pump 133, for example, is energized byclosing switch 127. Triple-pole switch 139 by-passes switches 127, 127'and 127" and can be used to simultaneously energize pumps 133, 133 and133" as described below.

The liquid to be injected against the lower face of a slide at station13 is stored in a container or bottle 129 located to the rear ofapparatus 11. A flexible, for example, plastic, tube 131 having one endinserted into the container and down into the stored liquid passesthrough a peristaltic pump 133 to a fitting 135. A second tube 137conducts the liquid from the fitting 135 to the orifice 111 in theplaten 105. The liquid thus flows through the orifice 111 only when theperistaltic pump 133 is operating. The pump 133 is electrically poweredand is controlled by switch 127 in response to movement of the slideengaging finger 123. Similar pumps 133' and 133" for stations 13 and 13"are similarly connected to liquid containers 129' and 129" and areoperated in a similar manner.

In order to have positive liquid flow through orifices 111, 111' and111" at predetermined times controlled by engagement of slides 17 withfingers 123, 123' and 123", the fluid lines 137, 137' and 137"communicating with orifices 111, 111' and 111" should be full of liquid.One convenient way to accomplish this is to operate pumps 133, 133 and133" to fill these lines prior to passing the slides 17 over platen 105.This specific pump priming action can be conveniently accomplished bypushing triple-pole priming switch 139 (FIGURES l, 2 and which by-passespump switches 127, 127' and 127" and thus energizes pumps 133, 133' and133" until liquid begins to flow out of orifices 111, 111' and 111".

Proper operation of this apparatus in applying liquid to slides, forexample, can only be accomplished if sufficient liquid is applied ateach liquid-applying station. It may be convenient to have indicatingmeans to show when the quantity of liquid in the bottles 129, 129' and129" is below a desired amount. One means for achieving this result isshown in FIGURE 4, and it is understood that this means is illustrativeonly and that other means may be employed if desired. As shown in FIGURE4, the container 129 is supported upon a spring platform 141 secured tointermediate wall 39. An arm 143 is secured. to the spring loadedplatform 141 and projects through an opening in wall 39 to a positionbelow microswitch 145 also mounted on wall 39. The spring action of theplatform is such that when the bottle contains more than a predeterminedminimum amount of liquid, its weight is sufiicient to depress theplatform 141 and arm 143 to a position out of actuating engagement withthe normally open microswitch 1 45. As liquid is pumped from the bottle,the spring platform will rise and, upon discharge of substantially allthe liquid, the platform, together with the arm 143, will rise, causingarm 143 to activate the microswitch 145 and illuminate indicator light147. The

circuitry is shown in FIGURE 5. Thus, a warning system is provided whichwill give an indication to the technician when the quantity of theliquid is low, thereby preventing improper staining and possible damageto the specimens carried on the slides. The illustrative apparatus hasonly a single indicator light governed by the liquid level in a singlebottle. It is understood that the inventive apparatus can have anindicator means of this type for each liquid container, or the singlelight can be governed by the quantity of liquid in a bottle dilferentfrom that shown in the figures. Other means can also be used which areresponsive to the amount of liquid in the liquid supply means.

As previously described, each glass slide 17 is returned to a generallyvertical position after passing the last liquid-applying station 13" sothat it is vertically disposed when it reaches the drying and collectionstation 19. To assure that the slide and the material carried thereonare completely dry before the slide has an opportunity to come incontact with another slide, a small blower fan 149 (FIGURES 2, 3, and 4)is disposed in the rear, lefthand corner of the apparatus 11 and directsa gentle current of air outwardly past the slowly advancing slides.Because the pitch of the helicals 53 and 55 is only slight at this finalstation, it takes the slides 17 a relatively long period of time to passthrough drying and collection station 19. Thus, each slide is exposed tothe air currents supplied by the fan 149 for a sufficient length of timeto assure that it is entirely dry.

As the glass slides 17 advance through the drying and collecting station19 and reach the end of the track formed by rails 47 and 49, they dropfrom between the helicals 53 and 55 into a collection container orbasket 151 which rests on a microswitch 89 positioned between collectioncontainer 151 and the base 21 of the apparatus 11. A slanted upper lip153 is provided at the top of the lefthand wall of the container 151, asseen in FIGURE 2, to direct the falling slides 17 into the container151. The short drop into the container 151 does not cause suflicientshock to break the slide and is not harmful to the stained materialcarried thereon.

A basket signal means is provided to signal the technician when thebasket 151 requires emptying. This means comprises the microswitch 89which is activated when the weight of the container 151 and a desirednumber of slides therein is reached. The movable contact of the switch89 normally is in electrical connection with contact (FIGURE 5)completing the connection between the motor 69 and a conventional powersource. As the slides drop into the basket the total weight of thebasket and slides increases. When the total weight of the basket andslides reaches a predetermined value representative of a desired numberof slides, the movable contact of the microswitch 89 moves out ofengagement with contact 90 and into engagement with contact 92. In thisposition the motor 69 and any operative peristaltic pumps 133, 133' and133" are stopped and a buzzer 155 is activated, signalling thetechnician that the basket is ready for removal and emptying. Further,an indicator light 157 is thereby illuminated. This protective deviceeliminates the posibility that the basket will overfill, causing theslides to jam in the helicals and consequently break. With thispossibility eliminated, the technicians mind is free from concern andcan be devoted to more essential tasks.

The above description was directed to one form of the invention whereinthe liquid to be applied to an object is mechanically pumped through anorifice. An alternative embodiment, shown in FIGURE 6, employs gravityfeed of the liquid from the storage containers positioned in an elevatedlocation with respect to the application orifice. In this embodiment,the illustrated liquid container 159 is supported atop the apparatuscover 29 in a suitable cradle 161 mounted on a valve 163. The valve 163includes a hollow needle 165 which extends through the cradle 161 and isadapted to puncture container 159, which is conveniently formed fromsoft plastic material. Thus, when the bottle 159 is pressed down on thevalve 163, it is securely impaled upon the hollow needle 165. The rateof flow through valve 163 can be regulated by means of a threaded valvestem 167 which screws into the front of the valve. From the valve 163,the liquid passes through a conduit 169 into a metering valve 171 whichconveniently may be solenoid-operated. From the metering valve 171, asecond piece of tubing 173 conducts the liquid to the orifice 111" inplaten 105". Ac-

cordingly, the liquid flows through orifice 111" when the valve 171 isopen, and the flow ceases when valve 171 is closed. The operation ofopening and closing valve 171 may be carried out in a manner describedabove for operating pump 133 wherein depending finger 123" engages aslide causing shaft 121" to rotate and actuate switch 127". Instead ofcontrolling a motor the switch would control the valve 171 in theembodiment of FIG- URE 6.

The above-described apparatus makes possible the conveying of generallyflat objects in a novel manner from an input station successively pastone or more treating stations in a predetermined orientation and thenceto a collecting station. In the illustrated form of the invention alarge number of slides can be automatically and successively treatedwith staining liquids. Thus, the tedious and repetitive job which labtechnicians were formerly required to perform to stain slides formicroscopic examinations is eliminated. The invention provides improvedeconomy in staining because only a small measure, usually about 1 cc.,of liquid needs to be expended for each slide at each station.Furthermore, superior quality and reproducibility of results is providedbecause the human factor is removed, insuring uniform performance ofeach step, and because each slide is always contacted with fresh liquid.

What is claimed is:

1. Apparatus for conveying along a predetermined path an object havingsimilar fiat end portions comprising a pair of similar helical elementsspaced a distance apart less than the length of the object toaccommodate an object which extends therebetween and is positioned withthe opposite flat end portions disposed between adjacent turns of saidhelical elements respectively, each of said helical elements having afirst portion in which adjacent convolutions thereof are spaced apart adistance slightly greater than the thickness of the end portions of saidobject and a second portion of greater pitch in which adjacentconvolutions thereof are spaced apart a distance slightly greater thanthe width of said object end portions, said helical elements also eachhaving an intermediate portion of increasing pitch which connects saidfirst and second portions, a track located between said helical elementsand adapted for engagement by an object being conveyed, and means forrotating said helical elements so as to cause an object extendingtherebetween and engaged by said first portions thereof to be movedalong said track and into engagement with said intermediate and secondportions thereof successively, the change in pitch of said helicalelements at said intermediate portions causing said object to be turnedfrom an initial orientation generally normal to the plane of said trackto a second orientation generally parallel to the plane of said track asit is advanced along said track in contact with said intermediateportions.

2. Apparatus according to claim 1 wherein at least one liquid applyingstation is positioned adjacent the track and also adjacent the secondportions of the helical elements.

3. Apparatus according to claim 2 wherein said liquid applying stationcomprises an element having a generally fiat surface positioned adjacentsaid track with the plane of said flat surface disposed parallel to andspaced slightly from the plane of the portion of the track adapted to becontacted by a flat object to be treated, said apparatus also havingmeans for supplying a liquid to said flat surface, the disposition ofsaid track with respect to said fiat surface affording limited spacebetween said fiat surface and the adjacent surface of a flat objectdisposed in engagement with said track and in face-to-face relation withsaid flat surface, said liquid being supplied in a quantity sufiicientto fill said space.

4. Apparatus for applying liquid to a microscope slide having agenerally flat face, which apparatus comprises a track adapted forengagement by and support of said microscope slide with its facedisposed parallel to the plane of the track, means for advancing saidmicroscope slide along said track, an element positioned adjacent saidtrack having a generally flat surface disposed parallel to but spacedslightly from the face of said microscope slide advanced along saidtrack and past said element, a source of liquid to be applied to saidface of said microscope slide, and means for supplying a predeterminedqua-ntity of liquid from said source onto said generally fiat surface soas to fill the space between said flat surface and said microscope slidewhen the microscope slide is disposed in face-to-face relation with saidfiat surface.

5. Apparatus according to claim 4 wherein the means for supplying theliquid onto said fiat surface includes a pump.

6. Apparatus according to claim 4 wherein the generally fiat surface ofthe element is provided with a plurality of grooves.

7. Apparatus according to claim 4 including indicating means to warn oflow liquid supply.

8. Apparatus according to claim 4 wherein the track supports themicroscope slide being treated and terminates short of the end of themeans for advancing the microscope slide so that the microscope slidedrops from the end of said track, there being means at the end of saidtrack for receiving the treated microscope slide as it drops from thetrack.

9. Apparatus according to claim 8 wherein indicating means is employedin combination with the means for receiving the microscope slide, saidindicating means being activated when a predetermined number ofmicroscope slides have been deposited in said receiving means.

10. An apparatus for treating material disposed on one face of a slidefor a predetermined period of time by effecting contact between thematerial and each of various liquids utilized incident to the stainingof the material, which apparatus comprises means for advancing a slidealong a predetermined path at a predetermined speed with the one facethereof oriented in a predetermined manner, at least two platens spacedfrom one another along said path, each of said platens defining agenerally fiat surface disposed so as to be parallel to and spacedslightly from the one face of a slide advanced along said path, meansfor supplying a previously unused portion of a different liquid to thefiat surface of each of said platens, each of said patens having alength measured in the direction of said path such that a slide advancedalong said path at said predetermined speed is in face-to-face relationwith said surface of each platen a length of time equal to thepredetermined period of contact time for the liquid supplied to therespective platen, said liquid being supplied to said surfaces in anamount sufficient to fill the space between the respective surfaces anda slide moved therepast.

References Cited UNITED STATES PATENTS 1,971,574 8/1934 Moon 2l4-72,886,200 5/1959 Thulke et al. 3,004,650 10/1961 Pettee. 3,027,8214/1'962 Wright 1184l0 X 3,169,887 2/1965 York.

WALTER A. SCHEEL, Primary Examiner.

J. P. MCINTOSH, Assistant Examiner.

